Eomysticetidae

Eomysticetidae
Temporal range: 33–Aquitanian Ma

Oligocene-earliest Miocene[1]

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Superfamily: Eomysticetoidea
Family: †Eomysticetidae
Genera

Eomysticetus
Matapanui
Micromysticetus
Tohoraata
Tokarahia
Waharoa
Yamatocetus

Eomysticetidae is a family of extinct mysticetes belonging to Chaeomysticeti (toothless mysticetes). It is one of two families in the basal chaeomysticete clade Eomysticetoidea (the other being Cetotheriopsidae).

Description

Restorations of Waharoa ruwhenua

Eomysticetids are united by the following combination of primitive and derived characters relative to more advanced chaeomysticetes (Balaenomorpha): zygomatic process without a supramastoid crest; reduction of the superior process of the periotic into a low ridge with anterior and posterior apices in medial or lateral view; blowholes situated ahead of the eyes; an elongated intertemporal region with long parietal and frontal exposures on the cranial vertex; elongated nasals; large coronoid processes of the mandibles; flat rostrum; laterally bowed mandibles; absence of functional teeth; and large mandibular foramina.[2]

Taxonomy

There are seven genera of Eomysticetidae: Eomysticetus, Matapanui, Micromysticetus, Tohoraata, Tokarahia, Waharoa and Yamatocetus.

Until the early 21st century, some of the known representatives of the family were thought to belong to then-wastebasket family Cetotheriidae, including Tokarahia lophocephalus and Tohoraata waitakiensis. However, in the original description of Eomysticetus, the similarities of "Mauicetus" lophocephalus to Eomysticetus, although Sanders and Barnes (2002) stopped short of assigning "M." lophocephalus to Eomysticetidae.[3] Subsequent studies confirmed the placement of "M." lophocephalus and "M." waitakiensis in Eomysticetidae.[4][5][6][7]

Paleobiology

As members of Chaeomysticeti, eomysticetids used their baleen plates to filter krill and other planktonic organisms. Although superficially similar to thalassotherian chaeomysticetes, their large mandibular canal indicates that they were incapable of lunge-feeding as in modern-day balaenopterids. A fatty pad on the mandibular canal suggests that eomysticetids could hear underwater.[6][7][8][9]

References

  1. ↑ R. W. Boessenecker; R. E. Fordyce (2017). "Cosmopolitanism and Miocene survival of Eomysticetidae (Cetacea: Mysticeti) revealed by new fossils from New Zealand". New Zealand Journal of Geology and Geophysics. 60 (2): 145–157. doi:10.1080/00288306.2017.1300176.
  2. ↑ Berta, A. and T.A. Deméré. (2009). Mysticetes, Evolution, pp. pp. 749-753, Encyclopedia of Marine Mammals (W.F. Perrin, B. Wursig, and J.G.M. Thewissen, eds.), 2nd ed., Academic Press, San Diego, CA.
  3. ↑ Sanders, A. E.; Barnes, L. G. (2002). "Paleontology of the Late Oligocene Ashley and Chandler Bridge Formations of South Carolina, 3: Eomysticetidae, a new family of primitive mysticetes (Mammalia: Cetacea)". Smithsonian Contributions to Paleobiology. 93: 313–356.
  4. ↑ Marx, F. G. (2011). "The more the merrier? A large cladistic analysis of mysticetes, and comments on the transition from teeth to baleen". Journal of Mammalian Evolution. 18: 77–100. doi:10.1007/s10914-010-9148-4.
  5. ↑ Steeman, M. E. (2007). "Cladistic analysis and a revised classification of fossil and recent mysticetes". Zoological Journal of the Linnean Society. 150: 875–894. doi:10.1111/j.1096-3642.2007.00313.x.
  6. 1 2 Boessenecker, R. W.; Fordyce, R. E. (2014). "A new Eomysticetid (Mammalia: Cetacea) from the Late Oligocene of New Zealand and a re-evaluation of 'Mauicetus' waitakiensis". Papers in Palaeontology. doi:10.1002/spp2.1005.
  7. 1 2 Boessenecker, Robert W.; Fordyce, R. Ewan (2015). "A new genus and species of eomysticetid (Cetacea: Mysticeti) and a reinterpretation of 'Mauicetus' lophocephalus Marples, 1956: Transitional baleen whales from the upper Oligocene of New Zealand". Zoological Journal of the Linnean Society. doi:10.1111/zoj.12297.
  8. ↑ "Eomysticetus whitmorei". NYIT College of Osteopathic Medicine. Retrieved October 2014.
  9. ↑ Boessenecker, RW; Fordyce, RE (2015). "Anatomy, feeding ecology, and ontogeny of a transitional baleen whale: a new genus and species of Eomysticetidae (Mammalia: Cetacea) from the Oligocene of New Zealand". PeerJ. 3: e1129. PMC 4570844 Freely accessible. PMID 26380800. doi:10.7717/peerj.1129.
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